(1) One who talks alot of non-sense and completely lies about something or someone. (hense having foam in ones mouth and not being able to understand them)
(2) An asshole
who says something about someone but doesn't have the courage to back it up.
(1)Dude, He's such a foamer hes choking himself.
(2)He talked shit and didn't even show up for the fight, what a foamer.